Okay, we know that \(\frac{5}{5}\) is equal to 1. Now if we divide 1 by 5 to see how many times 5 can go into 1 we see that 1÷5 or \(\frac{1}{5}\) = .2
So every \(\frac{1}{5}\) is equal to .2
Now we can multiply the .2 by 4 to see what \(\frac{4}{5}\) is equal to because \(\frac{1}{5} *4= \frac{4}{5}\)
And 4 * .2= .8
Hope this helped! :)